1. Field of the Invention
The present invention relates to a rollover protection system for automobiles, comprising an extensible rollover body held in an initial position by means of a holding device and secured against retraction, in a functional position by means of a locking device, and comprising an extension drive and an actuator for releasing the holding device.
Such rollover protection systems are used for the equipment of automobiles that do not offer sufficient protection for the passengers in case of a rollover, such as convertibles, where no roof is provided, or where the roof can be removed or folded away and where rigid, non-extensible rollover bodies are not desirable for aesthetic reasons.
The rollover bodies must be secured against inadvertent extension in a retracted initial position, and the extended rollover body must be secured against retraction in the functional position.
2. Description of Related Art
Mechanically biased springs or other stored-energy means which are blocked in the initial position by means of a releasable holding device, are used in many instances as an extension drive. In a similar way to airbags, a signal is generated by acceleration sensors, which triggers the activation of the rollover protection system, wherein the holding device is released by means of an actuator and the extension of the rollover body is enabled. Such a holding device is described in German Patent Specification 100 27 753 C1.
In the functional position, the extended rollover body is intended to support the overturned vehicle on the ground and to provide a protective space for the passengers. In this position, the rollover body must be locked against retraction, which is often realized by means of detent protrusions or the like biased in the engagement direction and automatically engaging a recess in the rollover body. Locking devices of this type are known from DE 100 27 753 C1 and DE 198 38 989 C1.
Hitherto the holding and locking functions have been treated as separate technical tasks, and thus separate devices have been designed for fixing the rollover body in the initial position and the functional position (cf. DE 100 27 753 C1). The technological and economic overhead is relatively high and a considerable drawback in the economic viability of such products.